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Phil, Mechanical Engineer
Category: HVAC
Satisfied Customers: 8695
Experience:  Retired HVAC/ Electrical & Boiler contractor. Industrial
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I have a carrier ducted air conditioning system 38QPA15-7

Customer Question

I have a carrier ducted air conditioning system 38QPA15-7
After installing a new contactor the system is now displaying error code 59 (Phase fault).
As the system is single phase this error is not correct but I understand this error is showing because the NR-1 board is not set up correctly.
Can you walk me through the steps to set the correct parameters.
Submitted: 1 year ago.
Category: HVAC
Expert:  BillyHvac replied 1 year ago.

I am very sorry your question has not been picked up yet.

I just logged on and found you had not been assisted.

Please let me know if you still need help and I will do my best. Please do not "Rate" as we have not worked toward an answer yet.

If you would like to proceed let me know by replying.

Customer: replied 1 year ago.
I still need help, error 59 is still there and it is impossible to start or re-set the system while this error persists.
Expert:  Phil replied 1 year ago.

If the system is over 5 years old, the odds are high that 59 is a bogus error code (about half of the error codes are not accurate on these systems, the older it is, the more likely the error code is not accurate).

However we can check it out,

First lets try switching Line 1 and Line 2 at the contactor you replaced, that is a bit of long shot but worth a try... and then check for voltage **between** line 1 and Line 2. Tell me what voltage read you get.

Depending on what you discover we can some further testing, and a heat stress test on the printed circuit card, depending on how old it is.,

We can go from there.